1. Field of the Invention
This invention relates to a feeder cap used for liquid containers of duplicating machines, etc.
2. Description of the Prior Art
Each liquid container of duplicating machines is usually provided with a feeder cap. When the liquid container is set upside down in a duplicating machine it supplies liquid through the feeder cap as a valve rod is axially moved by the action of a float. Because the valve rod is designed to be moved very easily in the axial direction in response to the action of the float, if the valve rod touches anything before the liquid container is set in the duplicating machine, the valve is liable to open and allow liquid to leak out of the container. Therefore, when the liquid container is not set in the duplicating machine, for instance when it is stored or transported, a regular cap is fitted to its mouth in place of the conventional feeder cap in order to close the mouth better. However, when the liquid container is shaken before use to stir liquid contained therein, the liquid may scatter out of the container and spot the users' clothes, etc. Also, when the regular cap is replaced by the feeder cap to set the container in the duplicating machine, the user's hands, clothes, etc. may be soiled by the liquid.
In an effort to overcome these disadvantages, the inventor has already provided an improved feeder cap as disclosed by Japanese Utility Model Laid-Open Publication No. Sho 53-45158 (Japanese Utility Model Application No. Sho 51-127066). The feeder cap of this Utility Model contains a valve mechanism comprising a valve and a valve seat, which mechanism does not operate when the container full of liquid is not set in the duplicating machine, so as to prevent the leakage of the liquid during the storage or transportation of the container. That is, as shown in FIG. 11, the feeder cap comprises a cap body 1', a hollow cylinder 8', through which liquid is supplied, disposed inside the cap body 1' so as to pass through it, a valve rod 9' disposed inside the hollow cylinder 8' so as to pass through it, an engagement piece 12' fixed to the upper end of the valve rod 9', said engagement piece 12' having inclined edges 15' under both ends thereof, a valve 13' fixed to the lower end of the valve rod 9', an auxiliary cap 2' detachably fitted to the upper portion of the hollow cylinder 8', a supporting plate 18' provided inside the auxiliary cap 2', an opening 19' corresponding to the engagement piece 12' being provided in the center of the supporting plate 18', and slopes 20' being formed only on the upper surfaces of both sides of the opening 19'. When the auxiliary cap 2' is turned prior to the storage or transportation of the container, the inclined edges 15' of the engagement piece 12' move onto the slopes 20' on both sides of the opening 19' to pull up the valve rod 9'. Then, the valve 13' is strongly pressed against the lower end (valve seat) of the hollow cylinder 8', and thus the leakage of liquid in the container 3 is completely prevented.
However, the aforesaid feeder cap has been found to have the following disadvantages; The feeder cap is designed only to pull up the valve rod 9' to press the valve 13' strongly against the lower end of the hollow cylinder 8' as mentioned above when the auxiliary cap 2' is turned, but the feeder cap does not have any means for pushing down the valve rod 9' to separate the valve 13' from the lower end of the hollow cylinder 8'. If the valve 13' remains strongly pressed against the lower end of the hollow cylinder 8' for a long period of time during the storage of the container, the valve 13' is liable to stick thereto due to the deposit of crystals from the liquid, so that it may not be moved easily. Then, even if the container 3 is set in the duplicating machine, the feeder cap in such a state will not be able to function at all. Therefore, it is necessary to eliminate the sticking of the valve 13' by separating it once from the lower end of the hollow cylinder 8' before the container 3 is set in the duplicating machine. However, because the feeder cap does not have any means for pushing down the valve rod 9' to separate the valve 13' from the lower end of the hollow cylinder 8', the user has to separate the valve 13' from the lower end of the hollow cylinder 8' by pushing down the valve rod 9' by hand after removing the auxiliary cap 2'. This is not only troublesome but also involves a possibility of liquid scattering out of the container and soiling the user's hands, clothes, etc.
Another improved feeder cap has already been disclosed by Japanese Utility Model Laid-Open Publication No. Sho 52-147656 (Japanese Utility Model Application No. Sho 51-54953). This is intended to be used for the same purpose as the above-mentioned feeder cap, but is different therefrom in the following points; The auxiliary cap is threadedly engaged with the cap body, the auxiliary cap is provided at its inside center with an internally threaded screw socket, and the valve rod is provided at its upper end with a disc fitting the internal thread of the screw socket, the pitch of the screw thread of said screw socket being slightly larger than the pitch of the interengaging screw threads of the auxiliary cap and the cap body. In this feeder cap, when the auxiliary cap is screwed, the disc fixed at the upper end of the valve rod is screwed into the screw socket and the valve rod is pulled up. Therefore, the valve fixed at the lower end of the valve rod is pressed against the valve seat so that the leakage of liquid in the container is completely prevented during storage or transportation.
However, this feeder cap has the following disadvantages: In the first place, it is rather complicated in construction, and is not necessarily easy to manufacture particularly because the disc at the upper end of the valve rod has to be precisely inclined so as to perfectly fit the internal thread of the screw socket. In the second place, when the auxiliary cap is screwed onto the cap body which has been fitted to the mouth of the container, it is very difficult to screw the disc fixed at the upper end of the valve rod into the screw socket inside the auxiliary cap because the valve rod is designed to move very sensitively in the axial direction.